越来越多的证据表明环境因素在影响抗生素抗性基因（ARGs）传播和抗性人类病原体繁殖方面中起了关键作用。然而，我们缺乏对生长和进化环境因素的理解，这些因素有助于抗生素耐药性的发展和传播。在这里，我们使用高通量定量PCR分析从海洋和河流海滩采集的61个土壤样本中分析了各种各样的ARGs，这些样本是人类活动的热点和环境ARGs可能传播给人类病原体的平台。我们确定了影响这些生态系统中ARGs的多样性，丰度和组成的主要非生物和生物因素。共检测到110种属于8个类别的主要抗生素耐药性的ARGs。 核心抗性基因组主要与β-内酰胺和多抗药性有关联，占ARGs总丰度的66.9％。在所有的样本中检测到oprJ基因是赋予多药抗性最广泛ARGs的亚型。总ARGs和核心抗性基因组的相对丰度与盐度相关性质显着相关，包括电导率和钠和氯的浓度。随机森林分析和结构方程模型显示，在考虑到多个驱动因素后，盐度是调节海滩土壤ARGs分布模式的最重要因素。这些研究结果表明，海滩土壤是一个丰富的ARGs储集层，盐度是影响土壤抵抗组分布模式的主要因素。
Growing evidence points to the pivotal role of the environmental factors in influencing the transmission of antibiotic resistance genes (ARGs) and the propagation of resistant human pathogens. However, our understanding of the ecological and evolutionary environmental factors that contribute to development and dissemination of antibiotic resistance is lacking. Here, we profiled a wide variety of ARGs using the high-throughput quantitative PCR analysis in 61 soil samples collected from ocean and river beaches, which are hotspots for human activities and platforms for potential transmission of environmental ARGs to human pathogens. We identified the dominant abiotic and biotic factors influencing the diversity, abundance and composition of ARGs in these ecosystems. A total of 110 ARGs conferring resistance to eight major categories of antibiotics were detected. The core resistome was mainly affiliated into β-lactam and multidrug resistance, accounting for 66.9% of the total abundance of ARGs. The oprJ gene conferring resistance to multidrug was the most widespread ARG subtype detected in all the samples. The relative abundances of total ARGs and core resistome were significantly correlated with salinity-related properties including electrical conductivity and concentrations of sodium and chloride. Random forest analysis and structural equation modelling revealed that salinity was the most important factor modulating the distribution patterns of beach soil ARGs after accounting for multiple drivers. These findings suggest that beach soil is a rich reservoir of ARGs and that salinity is a predominant factor shaping the distribution patterns of soil resistome.
